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|
#include "PerimeterGenerator.hpp"
#include "ClipperUtils.hpp"
#include "ExtrusionEntityCollection.hpp"
#include "BridgeDetector.hpp"
#include "Geometry.hpp"
#include <cmath>
#include <cassert>
namespace Slic3r {
void PerimeterGenerator::process()
{
// other perimeters
this->_mm3_per_mm = this->perimeter_flow.mm3_per_mm();
coord_t perimeter_width = this->perimeter_flow.scaled_width();
coord_t perimeter_spacing = this->perimeter_flow.scaled_spacing();
// external perimeters
this->_ext_mm3_per_mm = this->ext_perimeter_flow.mm3_per_mm();
coord_t ext_perimeter_width = this->ext_perimeter_flow.scaled_width();
coord_t ext_perimeter_spacing = this->ext_perimeter_flow.scaled_spacing();
coord_t ext_perimeter_spacing2 = this->ext_perimeter_flow.scaled_spacing(this->perimeter_flow);
// overhang perimeters
this->_mm3_per_mm_overhang = this->overhang_flow.mm3_per_mm();
// solid infill
coord_t solid_infill_spacing = this->solid_infill_flow.scaled_spacing();
// Calculate the minimum required spacing between two adjacent traces.
// This should be equal to the nominal flow spacing but we experiment
// with some tolerance in order to avoid triggering medial axis when
// some squishing might work. Loops are still spaced by the entire
// flow spacing; this only applies to collapsing parts.
// For ext_min_spacing we use the ext_perimeter_spacing calculated for two adjacent
// external loops (which is the correct way) instead of using ext_perimeter_spacing2
// which is the spacing between external and internal, which is not correct
// and would make the collapsing (thus the details resolution) dependent on
// internal flow which is unrelated.
coord_t min_spacing = perimeter_spacing * (1 - INSET_OVERLAP_TOLERANCE);
coord_t ext_min_spacing = ext_perimeter_spacing * (1 - INSET_OVERLAP_TOLERANCE);
// prepare grown lower layer slices for overhang detection
if (this->lower_slices != NULL && this->config->overhangs) {
// We consider overhang any part where the entire nozzle diameter is not supported by the
// lower layer, so we take lower slices and offset them by half the nozzle diameter used
// in the current layer
double nozzle_diameter = this->print_config->nozzle_diameter.get_at(this->config->perimeter_extruder-1);
this->_lower_slices_p = offset(*this->lower_slices, float(scale_(+nozzle_diameter/2)));
}
// we need to process each island separately because we might have different
// extra perimeters for each one
int surface_idx = 0;
for (const Surface &surface : this->slices->surfaces) {
// detect how many perimeters must be generated for this island
int loop_number = this->config->perimeters + surface.extra_perimeters - 1; // 0-indexed loops
surface_idx++;
if (this->config->only_one_perimeter_top && this->upper_slices == NULL){
loop_number = 0;
}
ExPolygons gaps;
//this var store infill surface removed from last to not add any more perimeters to it.
ExPolygons stored;
ExPolygons last = union_ex(surface.expolygon.simplify_p(SCALED_RESOLUTION));
if (loop_number >= 0) {
// In case no perimeters are to be generated, loop_number will equal to -1.
std::vector<PerimeterGeneratorLoops> contours(loop_number+1); // depth => loops
std::vector<PerimeterGeneratorLoops> holes(loop_number+1); // depth => loops
ThickPolylines thin_walls;
// we loop one time more than needed in order to find gaps after the last perimeter was applied
for (int i = 0;; ++ i) { // outer loop is 0
//store surface for bridge infill to avoid unsupported perimeters (but the first one, this one is always good)
if (this->config->no_perimeter_unsupported && i == this->config->min_perimeter_unsupported
&& this->lower_slices != NULL && !this->lower_slices->expolygons.empty()) {
//compute our unsupported surface
ExPolygons unsupported = diff_ex(last, this->lower_slices->expolygons, true);
if (!unsupported.empty()) {
//remove small overhangs
ExPolygons unsupported_filtered = offset2_ex(unsupported, -(float)(perimeter_spacing), (float)(perimeter_spacing));
if (!unsupported_filtered.empty()) {
//to_draw.insert(to_draw.end(), last.begin(), last.end());
//extract only the useful part of the lower layer. The safety offset is really needed here.
ExPolygons support = diff_ex(last, unsupported, true);
if (this->config->noperi_bridge_only && !unsupported.empty()) {
//only consider the part that can be bridged (really, by the bridge algorithm)
//first, separate into islands (ie, each ExPlolygon)
int numploy = 0;
//only consider the bottom layer that intersect unsupported, to be sure it's only on our island.
ExPolygonCollection lower_island(support);
BridgeDetector detector(unsupported_filtered,
lower_island,
perimeter_spacing);
if (detector.detect_angle(Geometry::deg2rad(this->config->bridge_angle.value))) {
ExPolygons bridgeable = union_ex(detector.coverage(-1, true));
if (!bridgeable.empty()) {
//simplify to avoid most of artefacts from printing lines.
ExPolygons bridgeable_simplified;
for (ExPolygon &poly : bridgeable) {
poly.simplify(perimeter_spacing/2, &bridgeable_simplified);
}
//offset by perimeter spacing because the simplify may have reduced it a bit.
//it's not dangerous as it will be intersected by 'unsupported' later
//FIXME: add overlap in this->fill_surfaces->append
// add overlap (perimeter_spacing/4 was good in test, ie 25%)
coord_t overlap = scale_(this->config->get_abs_value("infill_overlap", unscale(perimeter_spacing)));
unsupported_filtered = intersection_ex(unsupported_filtered, offset_ex(bridgeable_simplified, overlap));
} else {
unsupported_filtered.clear();
}
} else {
unsupported_filtered.clear();
}
} else {
//only consider the part that can be 'bridged' (inside the convex hull)
// it's not as precise as the bridge detector, but it's better than nothing, and quicker.
ExPolygonCollection coll_last(support);
ExPolygon hull;
hull.contour = coll_last.convex_hull();
unsupported_filtered = intersection_ex(unsupported_filtered, ExPolygons() = { hull });
}
if (!unsupported_filtered.empty()) {
//and we want at least 1 perimeter of overlap
ExPolygons bridge = unsupported_filtered;
unsupported_filtered = intersection_ex(offset_ex(unsupported_filtered, (float)(perimeter_spacing)), last);
// remove from the bridge & support the small imperfections of the union
ExPolygons bridge_and_support = offset2_ex(union_ex(bridge, support, true), perimeter_spacing/2, -perimeter_spacing/2);
// make him flush with perimeter area
unsupported_filtered = intersection_ex(offset_ex(unsupported_filtered, (float)(perimeter_spacing / 2)), bridge_and_support);
//add this directly to the infill list.
// this will avoid to throw wrong offsets into a good polygons
this->fill_surfaces->append(
unsupported_filtered,
stInternal);
// store the results
last = diff_ex(last, unsupported_filtered, true);
//remove "thin air" polygons
for (int i = 0; i < last.size();i++) {
if (intersection_ex(support, ExPolygons() = { last[i] }).empty()) {
this->fill_surfaces->append(
ExPolygons() = { last[i] },
stInternal);
last.erase(last.begin() + i);
i--;
}
}
}
}
}
}
// We can add more perimeters if there are uncovered overhangs
// improvement for future: find a way to add perimeters only where it's needed.
// It's hard to do, so here is a simple version.
bool has_overhang = false;
if (this->config->extra_perimeters /*&& i > loop_number*/ && !last.empty()
&& this->lower_slices != NULL && !this->lower_slices->expolygons.empty()){
//split the polygons with bottom/notbottom
ExPolygons unsupported = diff_ex(last, this->lower_slices->expolygons, true);
if (!unsupported.empty()) {
//only consider overhangs and let bridges alone
if (true) {
//only consider the part that can be bridged (really, by the bridge algorithm)
//first, separate into islands (ie, each ExPlolygon)
int numploy = 0;
//only consider the bottom layer that intersect unsupported, to be sure it's only on our island.
ExPolygonCollection lower_island(diff_ex(last, unsupported, true));
BridgeDetector detector(unsupported,
lower_island,
perimeter_spacing);
if (detector.detect_angle(Geometry::deg2rad(this->config->bridge_angle.value))) {
ExPolygons bridgeable = union_ex(detector.coverage(-1, true));
if (!bridgeable.empty()) {
//simplify to avoid most of artefacts from printing lines.
ExPolygons bridgeable_simplified;
for (ExPolygon &poly : bridgeable) {
poly.simplify(perimeter_spacing / 2, &bridgeable_simplified);
}
if (!bridgeable_simplified.empty())
bridgeable_simplified = offset_ex(bridgeable_simplified, perimeter_spacing/1.9);
if (!bridgeable_simplified.empty()) {
//offset by perimeter spacing because the simplify may have reduced it a bit.
unsupported = diff_ex(unsupported, bridgeable_simplified, true);
}
}
}
} else {
ExPolygonCollection coll_last(intersection_ex(last, offset_ex(this->lower_slices->expolygons, -perimeter_spacing / 2)));
ExPolygon hull;
hull.contour = coll_last.convex_hull();
unsupported = diff_ex(offset_ex(unsupported, perimeter_spacing), ExPolygons() = { hull });
}
if (!unsupported.empty()) {
//add fake perimeters here
has_overhang = true;
}
}
}
// Calculate next onion shell of perimeters.
//this variable stored the nexyt onion
ExPolygons next_onion;
if (i == 0) {
// compute next onion, without taking care of thin_walls : destroy too thin areas.
if (!this->config->thin_walls)
next_onion = offset_ex(last, -(float)(ext_perimeter_width / 2));
// look for thin walls
if (this->config->thin_walls) {
// the minimum thickness of a single loop is:
// ext_width/2 + ext_spacing/2 + spacing/2 + width/2
next_onion = offset2_ex(
last,
-(float)(ext_perimeter_width / 2 + ext_min_spacing / 2 - 1),
+(float)(ext_min_spacing / 2 - 1));
// detect edge case where a curve can be split in multiple small chunks.
ExPolygons no_thin_onion = offset_ex(last, -(float)(ext_perimeter_width / 2));
if (no_thin_onion.size()>0 && next_onion.size() > 3 * no_thin_onion.size()) {
//use a sightly smaller spacing to try to drastically improve the split
ExPolygons next_onion_secondTry = offset2_ex(
last,
-(float)(ext_perimeter_width / 2 + ext_min_spacing / 2.5 - 1),
+(float)(ext_min_spacing / 2.5 - 1));
if (abs(((int32_t)next_onion.size()) - ((int32_t)no_thin_onion.size())) >
2*abs(((int32_t)next_onion_secondTry.size()) - ((int32_t)no_thin_onion.size()))) {
next_onion = next_onion_secondTry;
}
}
// the following offset2 ensures almost nothing in @thin_walls is narrower than $min_width
// (actually, something larger than that still may exist due to mitering or other causes)
coord_t min_width = (coord_t)scale_(this->ext_perimeter_flow.nozzle_diameter / 3);
ExPolygons no_thin_zone = offset_ex(next_onion, (float)(ext_perimeter_width / 2));
// medial axis requires non-overlapping geometry
ExPolygons thin_zones = diff_ex(last, no_thin_zone, true);
//don't use offset2_ex, because we don't want to merge the zones that have been separated.
ExPolygons expp = offset_ex(thin_zones, (float)(-min_width / 2));
//we push the bits removed and put them into what we will use as our anchor
if (expp.size() > 0) {
no_thin_zone = diff_ex(last, offset_ex(expp, (float)(min_width / 2)), true);
}
// compute a bit of overlap to anchor thin walls inside the print.
for (ExPolygon &ex : expp) {
//growing back the polygon
//a vary little bit of overlap can be created here with other thin polygon, but it's more useful than worisome.
ExPolygons ex_bigger = offset_ex(ex, (float)(min_width / 2));
if (ex_bigger.size() != 1) continue; // impossible error, growing a single polygon can't create multiple or 0.
ExPolygons anchor = intersection_ex(offset_ex(ex, (float)(min_width / 2) +
(float)(ext_perimeter_width / 2), jtSquare), no_thin_zone, true);
ExPolygons bounds = union_ex(ex_bigger, anchor, true);
for (ExPolygon &bound : bounds) {
if (!intersection_ex(ex_bigger[0], bound).empty()) {
//be sure it's not too small to extrude reliably
if (ex_bigger[0].area() > min_width*(ext_perimeter_width + ext_perimeter_spacing2)) {
// the maximum thickness of our thin wall area is equal to the minimum thickness of a single loop
ex_bigger[0].medial_axis(bound, ext_perimeter_width + ext_perimeter_spacing2, min_width,
&thin_walls, this->layer_height);
}
break;
}
}
}
}
} else {
//FIXME Is this offset correct if the line width of the inner perimeters differs
// from the line width of the infill?
coord_t distance = (i == 1) ? ext_perimeter_spacing2 : perimeter_spacing;
if (this->config->thin_walls){
// This path will ensure, that the perimeters do not overfill, as in
// prusa3d/Slic3r GH #32, but with the cost of rounding the perimeters
// excessively, creating gaps, which then need to be filled in by the not very
// reliable gap fill algorithm.
// Also the offset2(perimeter, -x, x) may sometimes lead to a perimeter, which is larger than
// the original.
next_onion = offset2_ex(last,
-(float)(distance + min_spacing / 2 - 1),
+(float)(min_spacing / 2 - 1));
} else {
// If "detect thin walls" is not enabled, this paths will be entered, which
// leads to overflows, as in prusa3d/Slic3r GH #32
next_onion = offset_ex(last, -(float)(distance));
}
// look for gaps
if (this->config->gap_fill_speed.value > 0 && this->config->fill_density.value > 0)
// not using safety offset here would "detect" very narrow gaps
// (but still long enough to escape the area threshold) that gap fill
// won't be able to fill but we'd still remove from infill area
append(gaps, diff_ex(
offset(last, -0.5f*distance),
offset(next_onion, 0.5f * distance + 10))); // safety offset
}
if (next_onion.empty()) {
// Store the number of loops actually generated.
loop_number = i - 1;
// No region left to be filled in.
last.clear();
break;
} else if (i > loop_number) {
if (has_overhang) {
loop_number++;
contours.emplace_back();
holes.emplace_back();
} else {
// If i > loop_number, we were looking just for gaps.
break;
}
}
for (const ExPolygon &expolygon : next_onion) {
contours[i].emplace_back(PerimeterGeneratorLoop(expolygon.contour, i, true, has_overhang));
if (! expolygon.holes.empty()) {
holes[i].reserve(holes[i].size() + expolygon.holes.size());
for (const Polygon &hole : expolygon.holes)
holes[i].emplace_back(PerimeterGeneratorLoop(hole, i, false, has_overhang));
}
}
last = std::move(next_onion);
//store surface for top infill if only_one_perimeter_top
if(i==0 && config->only_one_perimeter_top && this->upper_slices != NULL){
//split the polygons with top/not_top
ExPolygons upper_polygons(this->upper_slices->expolygons);
ExPolygons top_polygons = diff_ex(last, (upper_polygons), true);
ExPolygons inner_polygons = diff_ex(last, top_polygons, true);
// increase a bit the inner space to fill the frontier between last and stored.
stored = union_ex(stored, intersection_ex(offset_ex(top_polygons, (float)(perimeter_spacing / 2)), last));
last = intersection_ex(offset_ex(inner_polygons, (float)(perimeter_spacing / 2)), last);
}
}
// re-add stored polygons
last = union_ex(last, stored);
// nest loops: holes first
for (int d = 0; d <= loop_number; ++d) {
PerimeterGeneratorLoops &holes_d = holes[d];
// loop through all holes having depth == d
for (int i = 0; i < (int)holes_d.size(); ++i) {
const PerimeterGeneratorLoop &loop = holes_d[i];
// find the hole loop that contains this one, if any
for (int t = d+1; t <= loop_number; ++t) {
for (int j = 0; j < (int)holes[t].size(); ++j) {
PerimeterGeneratorLoop &candidate_parent = holes[t][j];
if (candidate_parent.polygon.contains(loop.polygon.first_point())) {
candidate_parent.children.push_back(loop);
holes_d.erase(holes_d.begin() + i);
--i;
goto NEXT_LOOP;
}
}
}
// if no hole contains this hole, find the contour loop that contains it
for (int t = loop_number; t >= 0; --t) {
for (int j = 0; j < (int)contours[t].size(); ++j) {
PerimeterGeneratorLoop &candidate_parent = contours[t][j];
if (candidate_parent.polygon.contains(loop.polygon.first_point())) {
candidate_parent.children.push_back(loop);
holes_d.erase(holes_d.begin() + i);
--i;
goto NEXT_LOOP;
}
}
}
NEXT_LOOP: ;
}
}
// nest contour loops
for (int d = loop_number; d >= 1; --d) {
PerimeterGeneratorLoops &contours_d = contours[d];
// loop through all contours having depth == d
for (int i = 0; i < (int)contours_d.size(); ++i) {
const PerimeterGeneratorLoop &loop = contours_d[i];
// find the contour loop that contains it
for (int t = d-1; t >= 0; --t) {
for (int j = 0; j < contours[t].size(); ++j) {
PerimeterGeneratorLoop &candidate_parent = contours[t][j];
if (candidate_parent.polygon.contains(loop.polygon.first_point())) {
candidate_parent.children.push_back(loop);
contours_d.erase(contours_d.begin() + i);
--i;
goto NEXT_CONTOUR;
}
}
}
NEXT_CONTOUR: ;
}
}
// at this point, all loops should be in contours[0]
ExtrusionEntityCollection entities = this->_traverse_loops(contours.front(), thin_walls);
// if brim will be printed, reverse the order of perimeters so that
// we continue inwards after having finished the brim
// TODO: add test for perimeter order
if (this->config->external_perimeters_first ||
(this->layer_id == 0 && this->print_config->brim_width.value > 0))
entities.reverse();
// append perimeters for this slice as a collection
if (!entities.empty())
this->loops->append(entities);
} // for each loop of an island
// fill gaps
if (!gaps.empty()) {
// collapse
double min = 0.2 * perimeter_width * (1 - INSET_OVERLAP_TOLERANCE);
double max = 2. * perimeter_spacing;
ExPolygons gaps_ex = diff_ex(
offset2_ex(gaps, -min/2, +min/2),
offset2_ex(gaps, -max/2, +max/2),
true);
ThickPolylines polylines;
for (const ExPolygon &ex : gaps_ex) {
//remove too small gaps that are too hard to fill.
//ie one that are smaller than an extrusion with width of min and a length of max.
if (ex.area() > min*max) {
ex.medial_axis(ex, max, min, &polylines, this->layer_height);
}
}
if (!polylines.empty()) {
ExtrusionEntityCollection gap_fill = this->_variable_width(polylines,
erGapFill, this->solid_infill_flow);
this->gap_fill->append(gap_fill.entities);
/* Make sure we don't infill narrow parts that are already gap-filled
(we only consider this surface's gaps to reduce the diff() complexity).
Growing actual extrusions ensures that gaps not filled by medial axis
are not subtracted from fill surfaces (they might be too short gaps
that medial axis skips but infill might join with other infill regions
and use zigzag). */
//FIXME Vojtech: This grows by a rounded extrusion width, not by line spacing,
// therefore it may cover the area, but no the volume.
last = diff_ex(to_polygons(last), gap_fill.polygons_covered_by_width(10.f));
}
}
// create one more offset to be used as boundary for fill
// we offset by half the perimeter spacing (to get to the actual infill boundary)
// and then we offset back and forth by half the infill spacing to only consider the
// non-collapsing regions
coord_t inset =
(loop_number < 0) ? 0 :
(loop_number == 0) ?
// one loop
ext_perimeter_spacing / 2 :
// two or more loops?
perimeter_spacing / 2;
// only apply infill overlap if we actually have one perimeter
coord_t overlap = 0;
if (inset > 0) {
overlap = scale_(this->config->get_abs_value("infill_overlap", unscale(inset + solid_infill_spacing / 2)));
}
// simplify infill contours according to resolution
Polygons pp;
for (ExPolygon &ex : last)
ex.simplify_p(SCALED_RESOLUTION, &pp);
// collapse too narrow infill areas
coord_t min_perimeter_infill_spacing = solid_infill_spacing * (1. - INSET_OVERLAP_TOLERANCE);
// append infill areas to fill_surfaces
//auto it_surf = this->fill_surfaces->surfaces.end();
this->fill_surfaces->append(
offset2_ex(
union_ex(pp),
-inset - min_perimeter_infill_spacing / 2 + overlap,
min_perimeter_infill_spacing / 2),
stInternal);
if (overlap != 0) {
ExPolygons polyWithoutOverlap = offset2_ex(
union_ex(pp),
-inset - min_perimeter_infill_spacing / 2,
min_perimeter_infill_spacing / 2);
this->fill_no_overlap.insert(this->fill_no_overlap.end(), polyWithoutOverlap.begin(), polyWithoutOverlap.end());
}
} // for each island
}
ExtrusionEntityCollection PerimeterGenerator::_traverse_loops(
const PerimeterGeneratorLoops &loops, ThickPolylines &thin_walls) const
{
// loops is an arrayref of ::Loop objects
// turn each one into an ExtrusionLoop object
ExtrusionEntityCollection coll;
for (PerimeterGeneratorLoops::const_iterator loop = loops.begin();
loop != loops.end(); ++loop) {
bool is_external = loop->is_external();
ExtrusionRole role;
ExtrusionLoopRole loop_role;
role = is_external ? erExternalPerimeter : erPerimeter;
if (loop->is_internal_contour()) {
// Note that we set loop role to ContourInternalPerimeter
// also when loop is both internal and external (i.e.
// there's only one contour loop).
loop_role = elrContourInternalPerimeter;
} else {
loop_role = elrDefault;
}
// detect overhanging/bridging perimeters
ExtrusionPaths paths;
if (this->config->overhangs && this->layer_id > 0
&& !(this->object_config->support_material && this->object_config->support_material_contact_distance.value == 0)) {
// get non-overhang paths by intersecting this loop with the grown lower slices
extrusion_paths_append(
paths,
intersection_pl(loop->polygon, this->_lower_slices_p),
role,
is_external ? this->_ext_mm3_per_mm : this->_mm3_per_mm,
is_external ? this->ext_perimeter_flow.width : this->perimeter_flow.width,
this->layer_height);
// get overhang paths by checking what parts of this loop fall
// outside the grown lower slices (thus where the distance between
// the loop centerline and original lower slices is >= half nozzle diameter
extrusion_paths_append(
paths,
diff_pl(loop->polygon, this->_lower_slices_p),
erOverhangPerimeter,
this->_mm3_per_mm_overhang,
this->overhang_flow.width,
this->overhang_flow.height);
// reapply the nearest point search for starting point
// We allow polyline reversal because Clipper may have randomly
// reversed polylines during clipping.
paths = (ExtrusionPaths)ExtrusionEntityCollection(paths).chained_path();
} else {
ExtrusionPath path(role);
path.polyline = loop->polygon.split_at_first_point();
path.mm3_per_mm = is_external ? this->_ext_mm3_per_mm : this->_mm3_per_mm;
path.width = is_external ? this->ext_perimeter_flow.width : this->perimeter_flow.width;
path.height = this->layer_height;
paths.push_back(path);
}
coll.append(ExtrusionLoop(paths, loop_role));
}
// append thin walls to the nearest-neighbor search (only for first iteration)
if (!thin_walls.empty()) {
ExtrusionEntityCollection tw = this->_variable_width
(thin_walls, erExternalPerimeter, this->ext_perimeter_flow);
coll.append(tw.entities);
thin_walls.clear();
}
// sort entities into a new collection using a nearest-neighbor search,
// preserving the original indices which are useful for detecting thin walls
ExtrusionEntityCollection sorted_coll;
coll.chained_path(&sorted_coll, false, erMixed, &sorted_coll.orig_indices);
// traverse children and build the final collection
ExtrusionEntityCollection entities;
for (std::vector<size_t>::const_iterator idx = sorted_coll.orig_indices.begin();
idx != sorted_coll.orig_indices.end();
++idx) {
if (*idx >= loops.size()) {
// this is a thin wall
// let's get it from the sorted collection as it might have been reversed
size_t i = idx - sorted_coll.orig_indices.begin();
entities.append(*sorted_coll.entities[i]);
} else {
const PerimeterGeneratorLoop &loop = loops[*idx];
ExtrusionLoop eloop = *dynamic_cast<ExtrusionLoop*>(coll.entities[*idx]);
ExtrusionEntityCollection children = this->_traverse_loops(loop.children, thin_walls);
if (loop.is_contour) {
if (loop.is_overhang && this->layer_id % 2 == 1)
eloop.make_clockwise();
else
eloop.make_counter_clockwise();
entities.append(children.entities);
entities.append(eloop);
} else {
eloop.make_clockwise();
entities.append(eloop);
entities.append(children.entities);
}
}
}
return entities;
}
ExtrusionEntityCollection PerimeterGenerator::_variable_width(const ThickPolylines &polylines, ExtrusionRole role, Flow flow) const
{
// this value determines granularity of adaptive width, as G-code does not allow
// variable extrusion within a single move; this value shall only affect the amount
// of segments, and any pruning shall be performed before we apply this tolerance
const double tolerance = scale_(0.05);
ExtrusionEntityCollection coll;
for (const ThickPolyline &p : polylines) {
ExtrusionPaths paths;
ExtrusionPath path(role);
ThickLines lines = p.thicklines();
for (int i = 0; i < (int)lines.size(); ++i) {
const ThickLine& line = lines[i];
const coordf_t line_len = line.length();
if (line_len < SCALED_EPSILON) continue;
double thickness_delta = fabs(line.a_width - line.b_width);
if (thickness_delta > tolerance) {
const unsigned short segments = ceil(thickness_delta / tolerance);
const coordf_t seg_len = line_len / segments;
Points pp;
std::vector<coordf_t> width;
{
pp.push_back(line.a);
width.push_back(line.a_width);
for (size_t j = 1; j < segments; ++j) {
pp.push_back(line.point_at(j*seg_len));
coordf_t w = line.a_width + (j*seg_len) * (line.b_width-line.a_width) / line_len;
width.push_back(w);
width.push_back(w);
}
pp.push_back(line.b);
width.push_back(line.b_width);
assert(pp.size() == segments + 1);
assert(width.size() == segments*2);
}
// delete this line and insert new ones
lines.erase(lines.begin() + i);
for (size_t j = 0; j < segments; ++j) {
ThickLine new_line(pp[j], pp[j+1]);
new_line.a_width = width[2*j];
new_line.b_width = width[2*j+1];
lines.insert(lines.begin() + i + j, new_line);
}
--i;
continue;
}
const double w = fmax(line.a_width, line.b_width);
if (path.polyline.points.empty()) {
path.polyline.append(line.a);
path.polyline.append(line.b);
// Convert from spacing to extrusion width based on the extrusion model
// of a square extrusion ended with semi circles.
flow.width = unscale(w) + flow.height * (1. - 0.25 * PI);
#ifdef SLIC3R_DEBUG
printf(" filling %f gap\n", flow.width);
#endif
path.mm3_per_mm = flow.mm3_per_mm();
path.width = flow.width;
path.height = flow.height;
} else {
thickness_delta = fabs(scale_(flow.width) - w);
if (thickness_delta <= tolerance) {
// the width difference between this line and the current flow width is
// within the accepted tolerance
path.polyline.append(line.b);
} else {
// we need to initialize a new line
paths.emplace_back(std::move(path));
path = ExtrusionPath(role);
--i;
}
}
}
if (path.polyline.is_valid())
paths.emplace_back(std::move(path));
// Append paths to collection.
if (!paths.empty()) {
if (paths.front().first_point().coincides_with(paths.back().last_point())) {
coll.append(ExtrusionLoop(paths));
} else {
//not a loop : avoid to "sort" it.
ExtrusionEntityCollection unsortable_coll(paths);
unsortable_coll.no_sort = true;
coll.append(unsortable_coll);
}
}
}
return coll;
}
bool PerimeterGeneratorLoop::is_internal_contour() const
{
// An internal contour is a contour containing no other contours
if (! this->is_contour)
return false;
for (const PerimeterGeneratorLoop &loop : this->children)
if (loop.is_contour)
return false;
return true;
}
}
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